Child Doc 3: Body Composition Data
Grace Rubin
2025-01-16
2.b. Overview
The EchoMRI produces the following measurements:
- Fat mass
- Lean mass
- Total water
- Free water
These are recorded as absolute masses in grams, but I have also converted them to percentage of body mass for an additional way to assess body composition.
Similar to the metabolic tests, each mouse was measured at baseline and endpoint. Therefore, we can assess the effects of hormone treatment via:
- Intragroup / intramouse longitudinal changes from baseline to endpoint
- Cross-sectional differences between groups at endpoint
- We can compare endpoint body comp features in hormone-exposed mice with results in saline-exposed mice within the same microbiome condition (Non-ABX or ABX) to quantify the effects of each hormone on body comp under a given gut microbiome environment.
- We can compare body comp features in mice exposed to the same hormone but under different microbiome conditions to isolate any additive or interaction effects of hormones and gut microbiome presence on glucose homeostasis.
2.b.i. Intragroup Longitudinal Changes in Body Comp
Longitudinal changes can be visually represented in a few dif ways:
- Box plots
- Stacked bar graphs (particularly for percentages)
- Line graphs
Lean mass (g)
NOTES:
Because the mice are getting older, we might expect absolute lean mass to increase across the board. That’s why looking at % can be useful too.
There are some outliers I could consider taking out. I didn’t for now…
Lean mass (%)
Fat mass (g)
Fat mass (%)
Total water (g)
Total water (%)
Free water (g)
Free water (%)
2.b.ii. Endpoint Body Comp in each Hormone Group vs Saline
Lean mass (g)
Lean mass (%)
Fat mass (g)
Fat mass (%)
Total water (g)
Total water (%)
Free water (g)
Free water (%)
2.b.iii. Endpoint Body Comp in each Hormone Group ABX vs Non-ABX
Lean mass (g)
Lean mass (%)
Fat mass (g)
Fat mass (%)
Total water (g)
Total water (%)
Free water (g)
Free water (%)
2.b.iv. Correlations of Body Comp with other Factors
Correlations with body weight
Does the relationship between these variables and total body weight
differ by ABX status?
No clear differences in relationship by ABX status.
Let’s plot absolute lean mass (g) vs absolute body weight (g) in each group.
To see if there are differences in this relationship between hormone
groups, we will have to filter to only include the endpoint values. This
means we will be working with very low sample sizes for a regression, so
these are probably going to be not informative graphs. But nonetheless
here they are!
How about lean mass percentage vs absolute body weight (g)?
Let’s plot absolute fat mass (g) vs absolute body weight (g)
How about free mass percentage vs absolute body weight (g)?
Not that interesting.